1. Field of the Invention
The present invention relates to an actinic-ray- or radiation-sensitive resin composition, a resist film therefrom and a method of forming a pattern therewith. The composition, resist film and method of forming a pattern according to the present invention can be used in, for example, a semiconductor production process for an IC, a photomask or the like, a circuit board production process for a liquid crystal, a thermal head or the like, a nanoimprint mold fabrication process and other photofabrication processes.
2. Description of the Related Art
Heretofore, the microfabrication by lithography using a photoresist composition is performed in the process for manufacturing semiconductor devices, such as an IC and an LSI. In recent years, the formation of an ultrafine pattern in the submicron region or quarter-micron region is increasingly demanded in accordance with the realization of high integration for integrated circuits. Accordingly, the trend of exposure wavelength toward a short wavelength, for example, from g-rays to i-rays and further to a KrF excimer laser light is seen. Further, the development of lithography using electron beams, X-rays, or soft X-rays such as EUV light, other than the excimer laser light, is now being promoted.
In particular, the lithography using electron beams is positioned as the next-generation or next-next-generation pattern forming technology. Resists of high sensitivity and high resolution are demanded for the lithography. Specifically, increasing the sensitivity is a very important task to be attained for the shortening of wafer processing time. However, the pursuit of increasing the sensitivity with respect to the resists for electron beams is likely to invite not only the lowering of resolving power but also the deterioration of line edge roughness. Thus, there is a strong demand for the development of resists that simultaneously satisfy these properties. Herein, the line edge roughness refers to the phenomenon that the edge at an interface of resist pattern and substrate is irregularly varied in the direction perpendicular to the line direction due to the characteristics of the resist, so that when the pattern is viewed from above, the pattern edge is observed uneven. This unevenness is transferred in the etching operation using the resist as a mask to thereby cause poor electrical properties resulting in poor yield. Especially in the nanoregion of 0.25 μm or less, the line edge roughness is now an extremely important theme in which improvement is to be attained. High sensitivity is in a relationship of trade-off with high resolution and good line edge roughness. How to simultaneously satisfy all of them is a critical issue.
With respect to development defects as well, suppression thereof is demanded. How to simultaneously satisfy all of high sensitivity, high resolution, good line edge roughness and development defects is a very important task.
The electron beam lithography utilized as a nanofabrication technology is now indispensable as a method of fabricating a photomask blank used in the production of a photomask for semiconductor manufacturing.